One of the fundamental operating components of galvanometer systems are bearings. Bearings and the peripheral components allow the high speed and precision operation of scanners and similar devices.
However, bearings are subject to stress and damage from the physical contact and environmental conditions. As the bearings begin to wear or develop divots, the tolerance of the entire system degrades. Other causes for degradation includes the bearing interface with the race assembly. Due to the degrading performance, eventually the system falls out of tolerance and requires maintenance. In some situations, bearing failure can shut down a critical manufacturing line or other high priority operation. Parts and personnel may not be at beckon call to repair the system.
In addition, due to the precise manufacturing requirements, the bearings may suffer from design problems or manufacturing defects that do not comply with the system requirements. Such errors require a means to detect and quantify the error in order to notify the manufacturer and maintain the high quality of the product.
There have been some attempts to alleviate the aforementioned problems. In U.S. Pat. No. 4,326,677, a monitoring circuit for detecting metallic contact between the high-speed spindle and the housing is disclosed. Such a condition alerts personnel to this condition to avoid more serious problems. Another monitoring circuit is shown in U.S. Pat. No. 5,226,736, wherein sensors measure the dimensions of cracks or pits in the race or between the race and rings. The data is communicated to the processing center that analyzes the data for fault conditions.
What is needed is a means of detecting bearing tolerance changes over time. Such a system would be able to detect variations in the operating performance of a galvanometer bearing set and alert operators to potential problems. Such a monitoring and detection system must be simple and cost-effective to use and operate, and be passively transparent such that it does not interfere with normal operation of the galvanometer device or system. One of the advantages of such a system would be to incorporate a tolerance margin that could be used by maintenance personnel to anticipate failures in advance, so that the necessary replacement or repair parts would be in stock and the unit scheduled for down-time and service prior to an actual failure.